1. Field of the Invention
The present invention relates to an orthopaedic implant, and, more particularly, to a tibial knee component.
2. Description of the Related Art
A tibial knee component is implanted within a proximal tibia and engages with a femoral component implanted within a distal femur. The tibial knee component typically includes a bearing which is immovably affixed to a tibial tray. The tibial tray includes a stem which is implanted within the intramedullary (IM) canal in the proximal tibia. The bearing may be in the form of a wear resistant and low friction material such as ultra high molecular weight polyethylene (UHMWPE) which is immovably attached to the tibial tray. Pivotal movement between the femoral component and the bearing surface of the bearing occurs with relatively low friction and low wear characteristics.
It is also known to provide a mobile bearing which moves relative to the tibial tray. During deep flexion between the femur and tibia, the bearing rotates about a longitudinal axis associated with a pivot point at the attachment location between the bearing and tibial tray. While some designs allow for 360 degrees of rotation between the mobile bearing and the tibial tray, most designs have a rotational limit provided. Although known designs are adequate to allow limited rotation between the bearing and tibial tray, they may be relatively complex and thus expensive to manufacture.
What is needed in the art is a tibial knee component with a mobile bearing which is easier to manufacture and still allows adequate movement between the bearing and tibial tray during deep flexion of the knee joint.